Immunization and challenge shown by hamsters infected withOpisthorchis viverrinifollowing exposure to gamma-irradiated metacercariae of this carcinogenic liver fluke

Abstract

Here we report findings to optimize and standardize conditions to attenuate metacercariae of Opisthorchis viverrini by ionizing radiation to elicit protective immune responses to challenge infection. Metacercariae were gamma-irradiated and the ability of irradiated metacercariae to prevent patent infection of challenge metacercariae in hamsters was determined, as well as their ability to induce a host antibody response. Metacercariae irradiated in a dose-dependent manner, with 3, 5, 10, 12, 20, 25 and 50 Gray, were used to infect Syrian golden hamsters by stomach gavage to ascertain the effect of irradiation on ability of the worms to establish infection. In addition, other hamsters were infected with metacercariae irradiated with 20–50 Gray, followed by challenge with intact/wild-type (non-irradiated) metacercariae to determine the protective effect as established by the numbers of adult flukes, eggs of O. viverrini in hamster faeces and anti-O. viverrini antibody titres. Significantly fewer worms were recovered from hamsters immunized with metacercariae irradiated at 20, 25 and 50 Gray than from control hamsters infected with intact metacercariae or 0 Gray, and the worms showed damaged reproductive organs. Faecal egg numbers were decreased significantly in hamsters immunized with 25 and 50 Gray metacercariae of O. viverrini. Moreover, hamsters administered metacercariae that were protected elicited a robust, specific anti-fluke immunoglobulin G response compared to control hamsters, suggesting a role for antibody in protection elicited by radiation-attenuated metacercariae.

Programmed knockout mutation of liver fluke granulin attenuates virulence of infection-induced hepatobiliary morbidity

“…Batches of MC were stored in 150 mM NaCl at 4°C. The newly excysted-juvenile flukes (NEJ) were liberated from MC by incubation in 0.25% trypsin in 1× PBS supplemented with 2× 200 U/ml penicillin, 200 μg/ml streptomycin (Gibco) (2× Pen/Strep) for 5 min at 37°C in 5% CO 2 atmosphere, after which NEJ were separated from the discarded cyst walls of the MC by mechanical passage through a 27G (insulin) needle (Papatpremsiri et al, 2015; Papatpremsiri et al, 2016). Before use, NEJ were transferred into RPMI medium supplemented with 1% glucose, 2 g/l NaHCO 3 , 2× Pen/Strep, 1μM E-64 (Thermo Fisher Scientific) for 60 min at 37°C in 5% CO 2 atmosphere.…”

Low Dose Gamma Irradiation of Trypanosoma evansi Parasites Identifies Molecular Changes That Occur to Repair Radiation Damage and Gene Transcripts That May Be Involved in Establishing Disease in Mice Post-Irradiation

“…Other potential irradiated parasite vaccines include those for schistosomiasis (47,54), parasitic bronchitis caused by dictyocaulus spp. (55,56) and Babesia (55,56).…”

Estudo das populações de linfócitos T e linfócitos B esplênicos e do sangue periférico de camundongos BALB/c imunizados com taquizoítos de <i>Toxoplasma gondii</i> irradiados.

“…A utilização da radiação ionizante, com intuito de produzir vacinas com parasitas irradiados, já foi associada a uma variedade de parasitas, como Schistosoma mansoni (Wales, Kusel, 1992); Opisthorchis viverrini (Papatpremsiri et al, 2014), Giardia lamblia (Sundermann, Estridge, 2010), Plasmodium falciparum (Hoffman, Doolan 2000), T. gondii (Hiramoto et al, 2000). Nesses organismos, a radiação afeta principalmente a capacidade da reprodução ou até mesmo da diferenciação do parasita, que normalmente estão associados no desenvolvimento da patologia, sugerindo que o dano principal para esse efeito esteja nos ácidos nucleicos dos agentes (Mirzayans et al, 2013).…”

“…Atualmente, a radiação ionizante foi utilizada como uma ferramenta para a produção de imunógenos para malária, em que esporozoítos irradiados de Plasmodium falciparum induzem uma proteção de 90% no hospedeiro após o desafio com esporozoítos virulentos, este modelo é usado como vacina para a prevenção de doença em países endémicos (Seder et al, 2013). As vacinas com radiação ionizante também foram desenvolvidas para vermes que ocorrem principalmente no Japão, China e Sudeste da Ásia, como opistorquíase, onde metacercárias de Opisthorchis viverrini irradiados induzem uma resposta imune protetora no hospedeiro após o desafio (Papatpremsiri et al, 2014).…”